Refrigerant receiver and oil separator



Jan. 6, 1959 EQJ. KOCHER 2,867,098

REFRIGERANT RECEIVER AND OIL SEPARATOR Filed Oct. 22, 1956 INVENTOR.

85% M MM A free/vars.

United States Patent REFRIGERANT RECEIVER AND (BIL SEPARATQR Erich J. Kocher, Milwaukee, Wis, assignor to The Vilter Manufacturing Co., Milwaukee, Wis, a corporation of Wisconsin Application October 22, 1956, Serial No. 617,585

2 Claims. (Cl. 62-473) The present invention relates generally to improvements in the art of refrigeration, and relates more particularly to improvements in the construction and operation of liquid refrigerant receivers embodying oil separating and return means therein.

A primary object of this invention is to provide an improved liquid refrigerant receiver and oil separator which is extremely simple and compact in construction and which is moreover highly efiicient in operation.

In refrigerating systems employing a refrigerant transfer compressor requiring lubrication of various parts, a certain amount of the lubricant escapes to the high pressure or discharge side and becomes mixed with the gaseous refrigerant being delivered from the compressor to the condenser. It is therefore customary practice to provide means for separating this objectionable lubricant from the refrigerant, and this separation is ordinarily accomplished by passing the mixture of gaseous refrigerant and lubricant through a separator interposed in the high pressure line between the compressor and the condenser with the recovered lubricant being returned to the compressor. However, because of the afiinity of the refrigerant in gaseous form with the lubricant, coupled with the relative- 1y high pressures and temperatures existing in the locality of separation, an objectionable quantity of lubricant normally remains entrained with the refrigerant and is conducted therewith to the condenser and receiver and then with the liquid refrigerant to the evaporator.

It is therefore a more specific object of my present invention to provide an improved refrigerant transfer system in which any lubricant entrained with the refrigerant is most effectively separated therefrom in the receiver after the refrigerant has been condensed to liquid form.

Another specific object of the invention is to provide an improved combination liquid receiver and lubricant separator for refrigeration systems which is exceedingly effective in removing any entrained lubricant from the liquid refrigerant conducted thereto and in minimizing the possibilities of having the lubricant transferred to the evaporator with the refrigerant.

Still another specific object of this invention is to provide a liquid refrigerant receiver and oil separator of novel and improved construction which may be readily constructed at relatively low cost and which consists of a minimum number of parts.

A further specific object of the present invention is to provide an improved refrigerant transfer system, which comprises, a refrigerant circulating compressor having its low pressure side communicable with the discharge line of an evaporator for receiving gaseous refrigerant therefrom, heat exchange means communicable with the high pressure side of the compressor for receiving gaseous refrigerant therefrom and condensing the same, a drum communicable with the heat exchange means for receiving liquid refrigerant therefrom, means in the drum for separating entrained lubricant from the liquid refrigerant conducted thereto, conduit means for conducting the liquid refrigerant from the drum to the evaporator, and means new Patented Jan. 6, i959 for conducting the separated lubricant from the drum to the low pressure side of the compressor.

An additional specific object of the present invention is to provide an improved liquid refrigerant receiver for refrigerant circulating systems, comprising, means forming a liquid receiving chamber, spaced liquid inlet and outlet conduits communicating with the interior of the chamber, baffle means within the chamber between the inlet and outlet for directing all incoming liquid toward the bottom of the chamber, a separating screen interiorly spanning the chamber below the outlet conduit and partitioning the chamber between the outlet conduit and the lower end of the baffle means, and means for withdrawing liquid from the space within the chamber below the screen.

These and other specific objects and advantages of the invention will become apparent from the following detailed description.

A clear conception of the several features constituting the present improvement and of the mode of constructing liquid refrigerant receivers and of utilizing the same in a typical refrigerant circulating system may be had by referring to the drawing accompanying and forming a part of this specification, wherein like reference characters designate the same or similar parts in the various views.

Fig. 1 is a diagrammatic illustration of a typical refrigerant' circulating system embodying a liquid receiver of my improved construction;

Fig. 2 is a part sectional side elevation of the improved liquid receiver and lubricant separator; and

Fig. 3 is a somewhat enlarged transverse vertical section through the receiver taken along the line 3-3 of Fig. 2.

While the invention has been shown and described herein as being embodied in a liquid receiver in which oil is separated from liquid refrigerant conducted thereto in a particular type of refrigerant circulating system in which the elements are diagrmmatically depicted, it should be understood that the structure of the combined receiver and separator may be modified for use in various types of refrigerant circulating systems wherein it is desirable to remove excess lubricant from the refrigerant being circulated. It is also contemplated that certain specific descriptive terms used herein shall be given the broadest possible interpretation consistent with the disclosure.

Referring to the drawing, the typical refrigerant circulating system shown therein as embod' ing the improved liquid receiver and lubricant separator comprises, in general, a refrigerant circulating compressor having its low pressure side communicable with the discharge line 6 of an evaporator, not shown, for receiving gaseous refrigerant therefrom, heat exchange means such as a condenser 8 communicable with the high pressure side of the compressor 5 through a line 7 for receiving gaseous refrigerant from the compressor and for condensing the same, means such as a horizontally disposed drum or tank 10 having an upper inlet 11 adjacent one end communicable through a line 9 with the condenser 8 for receiving liquid refrigerant from the condenser, means such as a baffle 12 located Within the chamber formed by the drum 1t) and extending downwardly toward but terminating above the bottom of the drum interior adjacent to the inlet 11 thereof for directing all incoming liquid toward the drum bottom, means such as a separating screen 13 interiorly spanning the drum it? from a lower portion of the baffle 12 to the end of the drum remote from the inlet 11 thereof to thereby segregate the drum interior into an upper refrigerant receiving and confining space 14 and a lower lubricant settling and confining space 15, an outlet conduit to extending into the upper space 15 of the drum 113 remote from the inlet 11 thereof and above the screen 13, means forming a secondary chamber or lubricant sump 17 for receiving lubricant settling therein from the space 15, a line 18 communicating with the space 14 within the drum through the outlet 16 thereof for conducting liquid refrigerant from the space 14 to the evaporator, and means such as a cnduit 19 communicating with the lubricant sump 17 and with the low pressure line 6 for conducting the separated lubricant from the sump to the low pressure side of the compressor 5 for reuse in lubricating the same.

The compressor 5, condenser 8 and the evaporator, which is not shown, may all be of standard construction, and a separator may also be interposed in the line 7 between the compressor and the condenser for initially separating lubricant from the gaseous refrigerant conducted through the line 7 in accordance with customary practice with the lubricant which is removed from the gaseous refrigerant being returned to the compressor for re-use. However, by reason of the effectiveness of the lubricant separating means provided in the improved receiver in which lubricant is removed from the refrigerant in liquid state, there is no real need for providing a lubricant separator in the line 7 and such device may accordingly be eliminated as shown. It should also be understood that various control valves and electrical equipment for effecting normal operation of the refrigerant circulating system may also be provided, and valves 21, 22, 23, 24, and 25 have been diagrammatically shown in the lines 6, 7, 9, 18 and 19 respectively. In addition, the drum is preferably provided with a vent 26 having a safety valve 27 therein, and to permit periodic drainage of the oil sump 17, this sump is preferably provided with a drain 28 and drain valve 29. In order to facilitate periodic inspection and to afford a ready check as to conditions within the liquid receiver 10, an indicating device 39 may be associated therewith, the indicating device or gauge 30 being of ordinary construction and provided with the usual valves. In addition to the manually operable valve 25 diagrammatically illustrated in the liquid injection and oil return line 19, this line is also preferably provided with a thermostatic expansion valve 31 for controlling liquid injection into the suction or low pressure line 6.

When the improved liquid received and separator 10 has been properly constructed and installed in the refrigerant circulating system as hereinabove described, the normal operation of the system is as follows: The compressor 5 is operable to create a low pressure condition within the line 6 from the evaporator to thereby draw gaseous refrigerant into its compression chamber and to force the compressed gaseous refrigerant through the line 7 to the condenser 8. Since the compressor 5 is normally lubricated by injecting oil directly into the suction or low pressure line, a certain amount of this oil is entrained with the gaseous refrigerant and is conducted with the refrigerant to the condenser. The gaseous refrigerant carrying entrained oil is thereupon liquified in the condenser 8 and liquid refrigerant and entrained oil passes from the condenser through the line 9 and inlet 11 into the drum-like receiver 10. As the liquid refrigerant and entrained lubricant enters the receiver 10, it is directed toward the bottom of the receiver by the bafile 12, and as the liquid level within the receiver 10 rises above the screen 13, this screen is effective to retard movement of the heavier oil into the space 14 and therefore confines the lubricant to the lower space 15 while the purified liquid refrigerant rises above the screen 13. The liquid refrigerant within the space 14 and from which lubricant has been removed is thereupon conducted through the outlet 16 and the line 18 to the evaporator, and the lubricant confined within the lower space 15 in the receiver thereupon settles and collects in the oil sump 17. Since the oil thus collected within the sump 17 is re-usable in the system, it is conducted through the conduit 19 and past the thermostatic expansion valve 31 into the low pressure line 6 for injection back into the compressor 5 with the gaseous refrigerant.

From the foregoing detailed description, it is believed apparent that the present invention contemplates the provision of a refrigerant circulating system in which oil is most effectively removed from the circulating refrigerant while such refrigerant is in liquid form. The improved system is extremely simple and most economical due to the efficient recovery of entrained lubricant from the refrigerant, and the need for using a separate separator in the system is obviated. The improved liquid receiver is of compact and simple construction and may be readily fabricated and interposed in refrigerant circulating systems such as described herein. The improved device has been actually tested, and as a matter of fact, commercial installations embodying the improvements have proven extremely satisfactory and highly eflicient in removing entrained oil from the refrigerant being circulated to the evaporator.

It should be understood that it is not desired or intended to limit this invention to the exact details of construction or to the precise mode of operation of the refrigerant circulating system or the liquid receiver for use in such system as herein specifically shown and described, since various modifications within the scope of the appended claims may occur to persons skilled in the art to which this invention pertains.

I claim:

1. A liquid receiver for refrigerant circulating systems, comprising, means forming a horizontally elongated receiving chamber for liquid refrigerant having lubricant entrained therein, spaced liquid inlet and outlet conduits communicating with the opposite extreme ends of the interior of said chamber, baflie means within the inlet end of said chamber between said inlet and said outlet for directing all incoming liquid toward the bottom of said chamber, a separating screen interiorly spanning said chamber from end to end and below said outlet conduit to provide an upper refrigerant confining space and an elongated lower separated lubricant confining space within said chamber, means forming a secondary chamber depending from and communicating with said lower lubricant confining space for receiving lubricant ettling therein, and a refrigerant circulating compressor for withdrawing lubricant from said secondary chamber for re-use in lubricating the compressor.

2. A liquid receiver for refrigerant circulating systems, comprising, a horizontally disposed and elongated drum forming a lubricant laden refrigerant receiving chamber, spaced inlet and outlet conduits for the refrigerant communicating with the interior of said chamber near the extreme opposite ends thereof, a downwardly directed baflle within said chamber adjacent to said inlet. and. between said inlet and said outlet, said baflle terminating above the bottom of said chamber for directing all incoming lubricant laden refrigerant at its inlet end toward said chamber bottom, a horizontally disposed separating screen interiorly spanning said chamber throughout its entire length from the lower end of said bafile to a point below said outlet conduit to segregate said chamber into an upper refrigerant confining space in open communication with said outlet conduit and a lower lubricant confining space, and a refrigerant circulating compressor for withdrawing lubricant from the lower lubricant confining space within said chamber for re-use in lubricating the compressor.

References Cited in the file of this patent UNITED STATES PATENTS 

